1. Field of the Invention
Compounds, compositions and methods for the treatment of immunologically-related diseases and disorders such as autoimmune disorders and organ graft rejection.
2. Related Art
Action of the immune system is known to be involved in immunologically-related diseases and disorders such as autoimmune disorders and in organ graft rejection (“OGR”). Hematopoietic, thymus-derived cells, (so-called “T cells”) have an important and pervasive role as regulators and effectors of the functions of the immune system. Hematopoietic cells, and T cells in particular have on their surfaces a major transmembrane glycoprotein designated CD45, characterized by a cluster of antigenic determinants. CD45 is also known as leukocyte common antigen (“LCA”). The cytosolic portion of CD45 has protein tyrosine phosphatase (“PTP”) activity and CD45 activity is known to be essential for TCR initiated T cell activation. Studies in CD45-deficient cell lines have shown that CD45 is a positive regulator of the T-Cell Receptor (“TCR”) and that CD45 functions in TCR regulation by dephosphorylating the src kinases p56lck and p59fyn, which allows autophosphorylation of the positive regulatory site on these enzymes; these reactions lead to downstream events and ultimately to T cell activation.
Available treatments for autoimmune disorders and OGR have therapeutic disadvantages. For example, Cyclosporin A, the drug most commonly used to treat OGR, has renal and CNS toxicity.